Idle speed fluctuates (MIL works OK, no DTCs set)
Diagnostic procedure
Do the ECM/PCM idle learn procedure.
Test the fuel pressure.
Test the injectors.
Troubleshoot the alternator FR signal circuit.
Inspect the PCV valve.
Test the throttle body.
Troubleshoot the A/C signal circuit.
Troubleshoot the VTEC system oil pressure.
Also check for
Fuel contamination
Intake vacuum leaks